Avian Metapneumovirus Infection Rhinotracheitis (Swollen Head Syndrome SHD) in Laying Hens
Happenings / Clinical Signs
Visibly sick birds
- Few visibly sick birds
- Usually less than 4% of the flock are affected
- Egg production may be affected
- Egg production drop gradually
- Low mortality or increases gradually
- Mortality rarely exceeds 2%
- Poor body fleshing condition
Head Comb Wattles Face Nostrils Sinuses Mount Beak Ear lobes
- Swelling of the Head
- Swelling of the periorbital and infraorbital sinuses
- Respiratory signs spread fast
- Widespread respiratory signs are usually present
As a result of secondary E. coli infection
- Cerebral disorientation
Neck wings breast abdomen shanks legs hocks feet joints vent skin
- Hens in lay may also present with prolapsed oviducts due to violent coughing
- Pale or loss of colour in brown-shelled eggs
- Misshapen eggs
The Avian metapneumovirus infection has been associated with swollen head syndrome (SHS) in chickens, which is characterized by the following clinical signs: swelling of the periorbital and infra-orbital sinuses, torticollis, cerebral disorientation and opisthotonus, as a result of secondary E coli infection. Usually less than 4% of the flock are affected, although, widespread respiratory signs are usually present. Mortality rarely exceeds 2%. The infection is associated with reduced egg production loss the shell colour and misshapen eggs.
- Causing Agents
- Avian metapneumovirus infection. Avian Metapneumoviruses are members of the subfamily Pneumoviridae, belonging to the family Paramixoviridae
- Affected Systems/Organs
- Respiratory, Reproductive and Neurological System
- Transmission is rapid through aerosols via the respiratory route. Transmission from parents is uncertain. Contaminated objects.
- Mainly Affects
- Egg production, Egg quality and Liveability
- Control respiratory stressors. Multivitamins. Good management practices. Good biosecurity.
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Can be managed with feed additives, off-the-shelf medications
- Diagnosis should be confirmed with rapid assays and/or a certified laboratory
- Veterinary intervention is recommended
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
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David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 115
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Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.
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Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.